We've been stationed in the DC area for a little over a year now. While I've been able to tour DC a couple of times, my husband hadn't so we've been hitting a lot of the sites and have learned a trick or two along the way. There are so many bases in the DC area: Andrews Air force Base, Anacostia-Bolling, Walter Reed Army Medical Center, Fort Meade, Fort Belvoir, there's the Naval Academy, Marine Corps in Quantico, and so many more... So if you are military, or just someone on their way to the DC area I'll try to add some of the tips we've learned so you can see all there is to see before heading off somewhere else.
On President's Day you either want to go to one of two places, Mount Vernon (George Washington's old estate), or to the Library of Congress. The reason President's Day is a good day to visit Mount Vernon is because it is the only day you can get in free of charge and admission is pretty pricey. You'll want to get there early so you can pick up a ticket to tour the house (they are first come first serve), and you'll also want to dress really warm because it's usually really cold around this time of year. If you have children, bring blankets, coats, and I'd also recommend that you bring a stroller so they don't have to walk too much. Because admission is free, it will be packed, but once you start roaming around it's not too bad. You can look all over the grounds, watch a film, visit George Washington's tomb (they will have a special speech usually sometime in the morning), and they had a certain time when actors pretend to be Martha and George Washington who kept in character and answered all you could ask about our dear first president and his wife. It's a really fun place to visit and if you like Historical Sites it's definitely a must see while you're here.
Since we went to Mount Vernon last year, we opted to visit the Library of Congress. We were surprised to find out that President's Day is only one of two days (I think Veteran's Day is the second day) when the reading room is open to the public. When you arrive you can choose to go on a free tour around the library, but be forewarned you won't be seeing many books. Instead your guide will focus on the ornate decorations and architecture. Kids and families can join a tour, but you can also walk around by yourselves as well. If you don't like crowds, I'd avoid going on President's Day since many schools and tourists come on President's Day to visit the reading room. If you don't mind crowds and are planning to go also be sure to get some pictures in front of the Congress and Senate Buildings since they are right next to the library.
If you don't like crowds, you should think about going to visit the Holocaust Museum. I'd visited the museum twice. Once during the Spring and then during the Summer. Both times I had to get there early and wait outside before they opened to get tickets to see the displays and upper floor in the museum. However, we learned that because Winter isn't their peak season, tickets aren't required. I believe they said they'll start handing out tickets again around March, but before then you're free to go visit the upper floor as you'd like. Anyhow, Since I'd visited the top level twice I told Daniel to go check it out while I stayed with the children and visited the more kid friendly part of the museum: Daniel's Story--where they walk you through a Jewish boy's life during WWII in a sensitive manner.
It's important to point out that they recommend that children are 14 or older before they go on the top floor since it gives guests a glimpse into the horrors of the Holocaust. Of course, as the parent you're allowed to decide whether you think your child is mature enough to visit this area of the museum. Since our kids weren't ready (and I'd already been), I was more then content visiting the other areas of the museum until Daniel was done. There really weren't many people there at all so my kids were able to watch all the videos, pull, open, and push any of the drawers, windows, and buttons they had for the kids to explore.
As a side note be prepared to go through a metal detector and have your bags scanned when you come to the museum and the library. They do this in all the museums that I've visited in DC so far. We'd heard that the Holocaust Museum doesn't allow food inside, so if you pack a lunch be prepared to eat it before you enter the building. As a side note, the Smithsonian Museums haven't stopped us from bringing a backpack with lunch inside.
As for parking...If you go early to Mount Vernon you should find a spot in one of their parking lots for free. In DC they normally advise you to take the Metro, but if you have a big family like we do, that may not work for you. We visited the Library of Congress first and found 2 hour parking on a side street close by. After we finished, we went drove by the Jefferson Memorial where they have three hour free parking along the River. Usually this area gets filled quickly so we normally arrive early in the morning to ensure we find a spot. However, there weren't many cars there at all on President's Day. From there we walked to the Holocaust Museum which is a bit of a walk, but not too bad. Another option would be to park in one of the garages. If you park in a garage you will still have a bit of a walk to your destination, but you won't have to hurry back before your 2-3 hours are up to avoid a parking ticket.
If you decide you want to use a parking garage, don't rely on your GPS to find one. Our GPS sent us on a wild goose chase when looking for a parking garage. Instead, look up a parking garage on the internet before you leave and type in the address they provide on your GPS or a place right next to it. We've found parking for $11-15 for the day (which is cheaper then paying for everyone to take the metro unless all your kids are younger than six) especially if you have to pay for parking at the Metro Station.
Whether you take the Metro, or drive I know you'll enjoy visiting these sites. There are so many things to do and see while you're in the DC area. Hopefully, you'll enjoy exploring as much as we have!